The needs of biomedicine and biotechnology require improved measurement devices and techniques for purposes of analysis, monitoring, and control. Electrochemical biosensors can provide a possible means of meeting such needs if capabilities can be extended to a wider range of biomolecules and more complex matrices. It is proposed to undertake two new initiatives involving a synthesis of biological and analytical concepts: (1) To employ chemoreceptors as molecular recognition elements for the purpose of developing receptor enzyme amplified assays. Drugs such as PCP (angel dust) and specifically targeted. (2) To develop probes for continuous monitoring of antigens using monoclonal antibodies immobilized at an electrode tip. It is expected that reversible and reusable sensors would result if competitive inhibition is carried out in a thin layer at the sensing surface. Through these research directions we hope to achieve simplification of existing bianalytical methods with savings of time and cost as well as the elimination of reagents and sample treatment steps.